<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>渐变的案例</title>
    <style>
      /* 笔记本本的案例*/
        .container {
          width: 600px;
          height: 800px;
          border: 1px solid black;
          margin: 0 auto;
          padding: 20px;
          background-clip: content-box;
          background-image: repeating-linear-gradient(transparent 0px,transparent 29px,grey 30px);
        }
    /*  立体球体的案例*/
        .ball {
          width: 200px;
          height: 200px;
          border-radius: 100px;
          background-color: grey;
          background-image: repeating-radial-gradient(at 80px 100px,white,grey);
        }
    </style>
</head>
<body>
    <div class="container"></div>
    <div class="ball"></div>
</body>
</html>